2001 gs starting/runnning issues

[k1llua]

Hello there,

I have read a good 20 to 30 posts now and I think I have some understanding of what could be wrong, still its my first 2 stroke engine and I am a bit lost at the moment.

Recently bought a 2001 gs that needed a bit of love. I rode it a bit last year and it started spraying a bit of water into the hull from the tune pipe gasket to the exhaust manifold. not a ton of water, I could just vacuum it up off the bottom after 30 mins. Like an inch after that long.

I repaired the leak by tapping new holes as the bolts were all threaded. It had a ton of jbweld around the joint, so I lightly buffed the junk off with a sanding disc. the manifold and tune pipe all got new gaskets.

Since I sorted that out, I got it started and it was running well enough in the driveway to take it to the water. Got it to the dock and discovered it has a small leak in the hull, so I popped it onto ahore and filled the holes. It had about 2 inches of water in it when I noticed.

Back out it died on me at full throttle. Just cut right out. Got it home and since then I replaced the starter relay, battery cables, new plugs, new fuel filter, new fuses, cleaned all the ignition coil contacts, cleaned out the fuel selector switch.

After this it didn't want to start until I put a bit of gas mix into the carb and held the throttle open while I cranked it. I ran the engine wot for a bit. Then put the air box silencer back on and took it out. It ran pretty nice for a full 25 mins. it sat for a full day then I took it out and about 100 yards out it died on me, same thing.

The battery seems to be fine. It reads around 12.7 v even after a few failed start attempts. Coil reads good resistance, starter turns really nice. The ignition system seems to be working, I have a spark plug checker but it's tough to see the red flash in the day light. It has been running so it must be producing spark.

The plug I took out today was fairly carbon fouled. This means that the engine is running lean?

I am going to start taking the air box off to clean the flame arrestor,and also start removing the carb for cleaning, as the ski still has quite a few gray fuel and oil lines.
Am I correct in assuming that the problem is likely in the carb? Is it possible that the rectifier isn't grounding the system properly and sometimes I'm not getting spark?
Thanks in advance, this forum is full of all kinds of great info.

K

 

[artr]

If it still has the gray fuel lines going to and from the carb then they need to be replaced by standard black fuel lines and the carb rebuilt using a genuine mikuni kit and following the carb rebuild post at the beginning of the forum. This should be done before running the ski again. If the gray lines are only on the vent lines to and from the gas tank than that is ok. I am not familiar with gray oil lines, mine are clear. If the small lines that run from the oil pump to the injection ports on the engine are original and brittle they should also be replaced along with the inline oil filter.

If you remove the gas input line from the carb you will probably see green goo that is from deterioration of the gray line from ethanol in the fuel. That green goo is in the carb blocking passages and the little fuel filter internal to the carb causing the engine to run lean and will lead to failure.

 

[k1llua]

Sorry, yes the oil lines are clear, but the oil lines around the carb/ oil injector are gray.

I will replace all gray lines with black. Probably have the carb cleaned out

 

[artr]

The small oil lines that feed oil from the oil pump I believe are tygon and are usually transparent so you can see the oil flow and if bubbles are present. The black fuel line are standard automotive fuel lines. If you go through the trouble to remove and open the carb to clean it you should replace the parts using a genuine mikuni rebuild kit following the procedure listed in the beginning of this forum or you problably will find youself having to do it again (unless you know this was recently done properly by the previous owner).

 

[JC-SUPERJET]

First, do a Compression check on both Cylinders, before chasing your tail all over the Ski.

Sounds like the Engine has seized several times already...

 

[k1llua]

I am going to begin taking the carb off this weekend. then ill start disassembly of the fuel system. I don't think there is any seizure, it has run pretty well when it actually starts.
i thought compression should also be within a reasonable range since it started and ran for over 20 minutes.

Can I test compression if the engine doesn't start?

 

[JC-SUPERJET]

Only need the Starter to spin to do Cylinder Compression tests...search the Forum to learn how.

 

[k1llua]

Only need the Starter to spin to do Cylinder Compression tests...search the Forum to learn how.

130 in the bow cylinder / 30 in the aft cylinder.. guess I need to open the top up and see what's going on now. Thanks for the help.

 

[k1llua]

I opened up the top today, it was a bit filthy in there so not a lot of prior maintenance. The seals are all a bit crusty and the two o rings that sit at the top of each cylinder were not intact.

If I spin to flywheel the cylinders move pretty nicely I think.

So now im mot sure if i should I try ro replace these seals and check compression again, or disassemble further in anticipation of replacing the pistons.

There's some corrosion and buildup around the outsode of the cylinder, I don't see or feel any scratches or large gouges inside them, pistons have some carbon ash on the top, unsure how to know if they see OK.

In order here pictures are of the left cylinder at the top and bottom of its crank cycle. Then the same for the right cylinder.

 

[k1llua]

I'm unsure if I am allowed to reply to.my own thread. So I apologize if I shouldn't. Didn't see it in the forum rules.

Anyways,
The cylinders came off today nicely. The pistons that was losing compression has basically no rings left on the one side. I am having a fairly easy time pulling bits off and reading the manual now, injust lack any 2 stroke experience.

If the cylinder ground both rings down, can I replace it with new standard bore pistons?

I don't see any damage to the sleeves.

Is disconnecting the drive shift from the crank really difficult? Might be easier to pull the whole engine now..

 

[mikidymac]

Those pistons and cylinders show no signs of lubrication.
Are you sure you had any oil in the injection system?

Yes, pull the retaining ring off the driveshaft after moving the stainless hat on the carbon seal. Then pull the pump, then the driveshaft and finally the engine.

With the cylinders lacking any trace of lubrication I would bet your crankshaft is toast also.

I can also see an inline automotive fuel filter in your picture that can definitely restrict fuel flow and cause a very lean condition.

You are going to have to at minimum, have the cylinders bored oversized and oversized pistons installed, completely go through the fuel system and oil system.

 

[k1llua]

Short update:

Cylinders bored out nicely, pistons are on the way in the mail. I got the jet pump off the back and the engine came out nicely.
I cleaned out the oil injector, checked all the holes etc. My rotary valve looks okay, a bit dirty so I cleaned it all up with part cleaner.

The old cylinder gasket is still sort of gummed onto the top of the bottom end, so do I just put a new gasket over it when I reassemble, or sand it off with a vacuum?

Photo attached

 

[burtshaver2021]

Use a gasket remover aerosol available at any auto parts store and a brass brush to remove the old gasket. Stuff some shop towels in the cylinder bores so you don’t get any dirt or gasket remover spray in there. Did the shop chamfer the ports after boring them out? Make sure your piston to cylinder wall clearance is within spec and check your ring end gap.

 

[burtshaver2021]

Did you figure out why the one cylinder lost compression?

 

[k1llua]

They did full service on the cylinders, and the compression loss was because on of the old pistons had its rings ground to flush with the piston head, scoring the inside of the cylinder pretty badly, so where it scored and had no ring left it was losing all its compression.

The machinist said I could have done a 0.4-0.6 mm bore, but since cylinders come in half increments I did a full 1.0 and got 83mm pistons.

I will get some gasket remover when I go to get more part cleaner.

Hilariously, as I started pulling some of the fuel circuit today, there was no filter in the fuel basket, so that's an issue..

 

[burtshaver2021]

There is a reason that cylinder did that though, you need to find out why and fix that issue or it will happen again. It would be different if both cylinders tested around 130ish pounds and the wear was from everyday wear and tear but when one cylinder goes way down like that there’s something that caused that to happen. Once you get the engine together you should do a leak down test on it to see if it’s sucking in air from the crankshaft oil seals. Also be a good idea to bench test the oil pump and check the fuel system to make sure it’s not sucking air somewhere. Did the fuel filter have an oring in it?

 

[k1llua]

The crank looks like it's in good shape, I didn't realize the inline fuel filter was on the main line, I thought it was on the reserve line, so I think it was running really lean for some time even before I bought it.

I took the whole oil injextor assembly apart today and cleaned it, it seemed pretty dirty when I sprayed it, working on the fuel and oil lines this week, so I'll see how bad the oil was. Probably wasn't even getting in at all.

 

[k1llua]

Small update:

All new fuel and oil.lines done, got a new filter for the main fuel line, and there is a good oring on it.

Bench tested oil injector, it worked well shooting oil into the little nozzles. New pistons arrived, need a new circlip tool so I'm waiting on that to arrive now haha.

Took the impeller oil out and got new oil for that as well. Nothing in there looks too bad.

 

[burtshaver2021]

Yes, I couldn’t imagine trying to get those circlips in without the tool but with it, it’s easy peasy. Is your machinist going to chamfer the ports? I’ve seen posts where they didn’t so good idea to mention that to them. Also, are you planning on doing a leak down test on the motor before you instal it?

 

[k1llua]

Tool arrived woo-hoo.. used it for 15 minutes and I expect I'll never use it again.

I had the lower piston ring on one of the heads break as I was putting the cylinder down, jammed on me somehow, anyways..

I assume I need a bra d new 83mm ring, and that the old rings that were intact she useless.

I'll see about having the shop across the road do a leakdown, I do not have the tool for that.

Thanks

 

[burtshaver2021]

You should be able to get everything you need to make a leak down tester for about 40.00. T fitting, barbed fitting for the 1/4” hose, a schrader valve and the gauge. I could post a pic of the one I made if you like? Other than that just an air compressor

 

[k1llua]

Ill look for a decent leak down tester, lots of them are around 40 dollars. I did a bemch compression test today, cold I got 130 on each cylinder quickly and it held.

When I get the engine back in I'll need to reassemble the whole jet pump prior to securing the engine, right? I marked where it was before, but I assume I should check to make the drives haft as true as possible.

 

[mikidymac]

You are not buying a leak down tester. You are going to pressure test the engine, two very different tests.

 

[k1llua]

I understand, the manual is pretty specific. I just lack the tools to perform the tests.

Is there any good way to center the drives shaft without the seadoo tool that they cite in the manual. Does anyone have a file for a 3d printable one, or a paper version..?

 

[mikidymac]

Nope, you need the correct tool or make one with a spare pump.